Tag: 500 sperms a second

If you are a man, in the last second your body produced at least 1,500 sperm cells. If you are a man with no balls, the number will be decreased significantly.

For the past 40 years scientists have thought stem cells in the testicles, Germlines, become sperm only through a simple, two-step process. Not so. Germline stem cells, it seems, can become sperm in several different ways, according to new experiments with mice.

“What we’re saying is there isn’t a strict linear progression from a stem cell to a sperm cell,” said study co-author Robert Braun, associate director at the Jackson Laboratory in Bar Harbor, Maine. “Sometimes the stem cells go through several cell divisions to get there, sometimes they don’t.”

What’s more, the researchers found that a cell that’s partway to becoming a sperm cell can revert back to being a germline stem cell—previously thought impossible.

For the new study, scientists genetically engineered mice so that their germline stem cells appeared fluorescent, allowing the team to watch the cells’ development.

The scientists also “labeled” specific cells within the mouse germline stem cells a certain color and observed what happened to them over a period of several days.

The research also revealed that sperm develop from a smaller subset of specialized germline stem cells in the testes than previously thought.

Sperm Live Fast, Die Young

Since sperm are short-lived, they must constantly be replenished, Braun noted—hence that 1,500-per-second production rate.